1. Field of the Invention
The invention relates to a connector for supplying electric power to devices in a metal case.
2. Description of the Related Art
Japanese Patent Unexamined Publication No. 2006-31962 discloses a connector assembly for supplying electric power to devices of an electric car or the like, such as a motor accommodated inside a metal case. The connector assembly has a device-side connector and an electric wire-side connector. The device-side connector is mounted in a mounting hole that penetrates the metal case and the wire-side connector is mounted on an end of a wire harness. The connectors are fit together to connect terminals of the connectors to each other.
A relay terminal is held by the device-side connector and is long and narrow in the direction in which the two connectors are fit together. The relay terminal is connected to a motor winding. One end of the relay terminal projects in the direction in which the two connectors are fit together and is connected to an electric wire-side terminal of the wire-side connector.
A wire harness and a connector for use in a power circuit of an electric car and the like have a shielding means to prevent irradiation of electromagnetic waves. More specifically, the connector is covered with a shielding shell and a bolt fixes the shielding shell to the metal case that accommodates a motor to achieve grounding between the shield shell and the metal case. The wire harness is covered by a tube consisting of braided wires for collectively shielding the electric wires. An end of the braided wire tube is connected to the shielding shell.
The portion where the braided wire tube and the shielding shell are connected to each other has the following construction. A wire deriving tube projects from the end wire-side connector housing opposite the device-side connector, and the wire harness extends through the wire deriving tube. A shielding tube is formed on the shielding shell that covers the electric wire-side connector housing and covers the wire deriving tube so that a predetermined gap is defined between the electric wire-deriving tube and the shielding tube. The end of the braided wire tube is fit on the front end of the shielding tube. A caulking ring is caulked around the end of the braided wire tube to conductively fix the braided wire tube to the shielding shell.
A shell-mounting piece is provided on the end of shielding shell near the metal case and is used with a bolt to fix the shielding shell to the metal case so that the shielding shell covers the electric wire-side connector housing. Additionally, the shielding tube of the shielding shell surrounds the periphery of the wire deriving tube with a predetermined gap between the shielding tube and the wire deriving tube. Thus, the wire harness derived from the wire deriving tube is surrounded by the braided wire tube.
Assembly of the above-described connector requires the braided wire tube to be fit on the shielding tube of the shielding shell and the end of the braided wire tube then must be caulked with the caulking ring. The braided wire tube consists of narrow metal wires that can be caught by a sharp cut surface at an edge of the shielding tube, thereby preventing a rapid fit-on operation.
To overcome the above-described problem, the front edge of the shielding tube may be formed with an inwardly curved guide ring. The curved guide ring enables the braided wire tube to be fit easily on the shielding tube of the shielding shell. However, the front end of the wire deriving tube may catch the guide ring while fixing the shielding shell to the metal motor case, with the shielding shell placed on the wire-side connector housing.
The above-described problem is illustrated in FIG. 12, which shows a shielding shell 1 with a shielding tube 2 and a guide ring 3 that is curved in at the front end of the shielding tube 2. The shielding shell 1 is placed on a wire-side connector housing 4 and a mounting piece 6 of the shielding shell 1 is bolted to a metal motor case 7. The wire-side housing 4 has an electric wire deriving tube 5 that penetrates through the guide ring 3 of the shielding tube 2 as the shielding shell 1 is placed on the wire-side housing 4. Thus, the inside diameter of the guide ring 3 must exceed the outer diameter of the wire-deriving tube 5.
The wire deriving tube 5 is biased with respect to the shielding tube 2 while fitting the shielding shell 1 on the wire-side housing 4, as shown near the top of FIG. 12, and the front of the wire deriving tube 5 may strike the guide ring 3.
The guide ring 3 may be pressed against the front end surface of the wire deriving tube 5 at a strong force when the mounting piece 6 of the shielding shell 1 is bolted to the motor case 7. As a result, the guide ring 3 and the shielding shell 1 may be deformed or the wire deriving tube 5 and the wire-side housing 4 may generate an excessive stress. As a result, the wire deriving tube 5 and the wire-side housing 4 may break or deform.
The invention has been made in view of the above-described situation. Therefore an object of the invention is to provide a connector with a shielding shell and a wire-side housing that will not deform or otherwise malfunction while fixing the shielding shell to a motor case.